Multiplier for dicing rate of geometry outside of the camera view.
The dicing rate of objects is gradually increased the further they are outside the camera view.
Lower values provide higher quality reflections and shadows for off screen objects,
while higher values use less memory.

Max Subdivisions

Stop subdividing when this level is reached even if the dice rate would produce finer tessellation.

Dicing Camera

Camera to use as reference point when subdividing geometry,
useful to avoid crawling artifacts in animations when the scene camera is moving.

These are global settings that apply to all instances of hair systems.
The resolution of the strands is controlled by the step values in particle settings.
Each hair system uses the material identified in the particle settings in the same way as Blender Internal.

See also

There are also object-level hair settings for each particle system which can be found
in the Hair Settings.

Use Hair

Enables rendering of hair particle systems.

Primitive

Triangles

Uses a triangle mesh.

Resolution

Number of times to subdivide the hair.
Higher values gives better quality results at the cost of increased memory usage.

Line Segments

Uses a straight curve primitive.

Curve Segments

Uses a smooth Cardinal curve primitive. These interpolate a path through the curve keys.
However, it renders slower than line segments.

Curve Subdivisions

The interpolated path is subdivided to give points to connect.
The parameter subdivisions sets the number of divisions used.

Shape

Thick

Cylindrical segments between two points.

Cull back-faces

Excludes strands emitted from the mesh backfacing the camera.

Ribbons

Are flat planes following the strand direction facing the camera.

Min Pixels

Strands that are further away will be made wider, which is compensated with transparency to keep the look similar.
This effect is only applied for camera rays. It works best with ribbon primitives.